The present invention relates to an electric motor and, particularly, to a brush electric motor.
Brush electric motors are used in many environments. One example environment is the cooling system of an automobile. For a specific example, a brush electric motor can be used to power and control the movement of a cooling fan for the engine of the automobile. For such an environment, if the fan locks (e.g., a foreign object prevents movement of the fan), a closed-circuit condition can occur in the armature of the motor, thereby resulting in the motor overheating. The overheating of the motor may cause damage to the motor and, possibly, the surrounding environment. It would be beneficial to have a self-contained solution for deactivating the brush motor when the brush motor overheats due to a lock condition.
In one embodiment, the invention provides an electric motor including an armature, a stator, and a plurality of brushes. The armature includes an armature winding and a commutator connected to the armature winding. The stator is disposed to magnetically interact with the armature. The brushes are disposed to frictionally engage with the commutator to controllably provide electric current to the armature winding via the commutator. The electric motor further includes an inductor (e.g., a wire-wound inductor) electrically connected in a series relationship with at least one of the brushes and a thermal cutoff device electrically connected in a series relationship with the inductor. The thermal cutoff device is disposed within at least a portion of the inductor.
Other features and embodiments of the invention will become apparent by consideration of the detailed description and accompanying drawings.